Explosive composition containing a vinylidene chloride polymeric latex

ABSTRACT

AN EXPLOSIVE COMPOSITION IS FORMED BY MIXING TOGETHER A PARTICULATE INORGANIC OXIDIZER, A SUBSTANTIALLY SATURATED AQUEOUS SOLUTION OF MAGNESIUM NITRATE, AMMONIUM NITRATE, OR AN AQUEOUS AMMONIACAL AMMONIUM NITRATE SOLUTION, A SETTING AGENT WHICH SETS SAID COMPOSITION TO A SOLID MATERIAL AND A SMALL BUT EFFECTIVE AMOUNT OF A POLYMERIC ORGANIC LATEX TO INCREASE THE PHYSICAL STRENGTH OF SAID EXPLOSIVE AND PERMITTING THE MIXTURE TO SET. CHLORINE CONTAINING ORGANIC POLYMERIC LATEXES ALSO INCREASE THE SENSITIVITY OF THE EXPLOSIVE COMPOSITION.

United States Patent Olhce 3,741,831 Patented June 26, 1973 3,741,831 EXPLOSIVE COMPOSITION CONTAINING A VINYLIDENE CHLORIDE POLYMERIC LATEX Richard L. Brennan, Midland, Mich., assignor to The Dow Chemical Company, Midland, Mich. No Drawing. Filed June 5, 1972, Ser. No. 259,842 Int. Cl. C06b 1/04 U.S. Cl. 149-41 13 Claims ABSTRACT OF THE DISCLOSURE An explosive composition is formed by mixing together a particulate inorganic oxidizer, a substantially saturated aqueous solution of magnesium nitrate, ammonium nitrate, or an aqueous ammoniacal ammonium nitrate solution, a setting agent which sets said composition to a solid material and a small but effective amount of a polymeric organic latex to increase the physical strength of said explosive and permitting the mixture to set. Chlorine containing organic polymeric latexes also increase the sensitivity of the explosive composition.

BACKGROUND OF THE INVENTION In U.S. Pat. 3,326,734 an explosive composition is taught and claimed comprising a particulate inorganic oxidizer,a substantially saturated solution selected from the group consisting of aqueous magnesium nitrate, aqueous ammonium nitrate and aqueous ammoniacal ammonium nitrate, and a setting agent which sets the explosive composition to a solid material containing solvent used in a liquid phase. The setting agent comprises certain inorganic oxides or salts. Other constituents that can be included are other fuel components such as particulate metals, organic materials such as alcohols, urea and the like. The present invention concerns an improvement in the composition disclosed in said patent No. 3,326,734. All the teachings of U.S. Pat. 3,326,734 are specifically incorporated herein by reference.

The present invention comprises adding to the composition of U.S. Pat. 3,326,734, during the manufacture thereof, a small but effective amount of a polymeric organic latex prior to the setting of said composition. Organic polymeric latexes which can be employed include, for example, various vinylidene-chloride latexes. Preferred latexes are those taught in U.S. Pat. 3,411,943. The teachings found at column 1, line 44 through column 2, line 31 of said patent are specifically incorporated herein by reference. Other organic polymeric latexes can be employed. Organic polymeric latex materials containing chlorine atoms in the polymer tend to, in addition to increasing the physical strength, increase the sensitivity of the explosive composition, i.e., decrease the critical diameter of the explosive.

Polymeric organic latex is employed in an amount ranging from about .1 to about 10% (based on the weight of the solids present in the latex) by weight of the explosive composition disclosed in U.S. Pat. 3,326,734.

The explosive composition of the invention is prepared in the following manner. The solid particulate oxidizer is blended with the setting agent, e.g. magnesium oxide and other solid components if used, e.g. particulate metals and the like and the saturated nitrate solution, and any other liquid component then added to this mixture. Preferably thelatex is added last and the mix cast into molds immediately thereafter before the latex coagulates and salts out.

As an example a composition of the present invention is prepared in the following manner. Particulate magnesium/aluminum alloy (50/50 by weight), 1053 grams is added to a mixing container. The particulate metal has a size distribution between 20 and +325 mesh U.S. Standard Sieve Series. To the particulate metal is added 982 grams of a fuel solution containing as parts by weight 50 ammonium nitrate, 21 H 0 and 31 beet sugar. To this mix is then added 750 grams of fine ground ammonium nitrate with mixing. Following this 210 grams of magnesium oxide is thoroughly mixed therein followed by 753 grams of additional fine ground ammonium nitrate. Finally 80 grams of a 50 percent solids latex of a polymer of 75 parts by weight vinylidene chloride, 25 parts chloride, 3 parts ethyl acrylate and 2 parts methyl methacrylate is thoroughly mixed with the other constituents and the composition is cast into a mold where it sets up to form a hard set mass.

EXAMPLE Various compositions Were prepared according to the procedure taught in U.S. Pat. 3,326,734. To certain of the compositions was added a latex comprising 50% by weight of an organic polymeric material comprising a polymer of 25 parts vinyl chloride, 75 parts vinylidene chloride, 3 parts ethyl acrylate, 2 parts methyl methacrylate and 50% by weight H O. Certain of the compositions were tested in a standard lead block deformation test, said test being well-known in the art and being described at column 4, lines 1-18 of U.S. Pat. 3,326,734.

Certain of the compositions were shot in a 2 inch diameter by 12 inch long tube, and the amount of material remaining following the shot was measured. This test is employed to compare the relative sensitivity (i.e. ability to sustain propagation) of various compositions. In these tests the compositions were all detonated employing a 40 gram high pressure booster. The temperature of the explosive at the time of detonation was about F.

Certain of the other compositions were cast into the 7 inch diameter spheres and the physical characteristics thereof (i.e. strength) determined.

The compositions and the results of the various tests performed thereon are set forth in the following table.

TABLE Parts by weight Fuel Density T ft i Test solucontrol Thio- Density, AH, tube, Physical Test type No. AN MgO Metal 1 tron 1 H2O agent Sulfur urea Latex gm./cc inches inches characteristics Lead block. 1 85.6 12 1. 05 Do. 2 85.6 12 1.16 D 3 85. 6 12 1. 16 D0 4 85.6 12 1.13 D0 5 85.6 12 1.12 Do 6 1, 503 211 1. 04 Case into 7 diameter sphere. 7 1, 503 211 0.92 Poor physical strength. Do 8 1, 503 210 0.92 Excellent physical strength. 2 x 12" tube-.- 9 300 42 1.11 5.25 Do 10 330 46.2 23 7. 25 11 564 79. 2 6. 5 12 300 42 6.6 13 1, 503 211 2. 0 Poor physical strength. 14 1, 503 210 6. 5 Excellent physical strength.

1 Particulate metal comprised a 50:50 part by weight Mg-Al alloy having particles between -1-325 mesh U.S. Standard Sieve. 1 Fuel solution comprises as parts by weight, 50 NH NO3, 21 I110, 31 beet sugar. 7

8 Metal com rised 396 parts of the 50:50 Mg-Al alloy and 66 parts flake Al. 4 Metal comgrised 210 parts of the 50:50 Mg-Al alloy and 35 parts flake Al.

What is claimed is:

1. An explosive composition comprising:

(a) from about 40 to about 75 parts by weight particulate ammonium nitrate;

(b) from about 20 to about 35 parts by weight of a solution selected from the group consisting of aqueous magnesium nitrate, aqueous ammonium nitrate and aqueous ammoniacal ammonium nitrate;

(c) at least about 2 parts by weight of a setting agent selected from the group consisting of alkaline earth metal oxide, zinc oxide, lead mono oxide, calcine dolomitic limestone, substantially anhydrous calcium sulfate, substntially anhydrous magnesium sulfate, substantially anhydrous sodium tetrapyrophosphate and substantially anhydrous sodium thiosulfate, said member being further characterized as setting said composition to a solid material which contains solvent used in the liquid phase; and

(d) an effective amount of a vinylidine chloride oganic polymeric latex to increase the strength of said set explosive composition.

2. The composition of claim 1 wherein said latex comcomprises, a percent by weight of solids in said latex, from about 0.1 to about 0.1 to about 10 percent of said explosive composition.

3. The composition as defined in claim 2 wherein the setting agent is an alkaline earth metal oxide and is characterized in that it reacts with the solvent of the nitrate solution over a period of time and sets said composition to a solid containing said solvent member.

4. The explosive composition as defined in claim 3 wherein the setting agent is magnesium oxide.

5. The explosive composition as defined in claim 3 and having up to about 50 parts by weight of a particulated light metal.

6. The explosive composition as defined in claim 2 which comprises:

(a) from about 50 to about 70 parts by weight prilled ammonium nitrate;

(b) from about 22 to about 28 parts by weight of a substantially saturated solution selected from the group consisting of aqueous magnesium nitrate, aqueous ammonium nitrate and aqueous ammoniacal ammonium nitrate, and

(c) from about 4 to about 8 parts by weight magnesium oxide to eifect solidification of said composition.

7. The explosive composition as defined in claim 6 and having from about 2 to about parts by weight of particulated aluminum.

8. The composition of claim 2 wherein said latex consists of a thermoplastic vinylidene chloride interpolymeric latex consisting essentially of from about 35 to about by weight of vinylidene chloride and from about 65 to about 10% by weight of a dissimilar interpolymerizable comonomer, as based on a total interpolymeric latex solids content of by weight.

9. A method for preparing a dense, water-resistant inorganic based explosive composition which comprises:

(a) blending from about 40 to about 75 parts by weight solid particulate ammonium nitrate with at least about 2 parts by weight of a member selected from the group consisting of alkaline earth metal oxides, zinc oxide, lead monoxide, calcined dolomitic limestone, substantially anhydrous calcium sulfate, substantially anhydrous magnesium sulfate, substantially anhydrous sodium tetrapyrophosphate and substantially anhydrous sodium thiosulfate, said member being further characterized in setting said composition to a solid material which contains solvent used in the liquid phase of a solution selected from the group consisting of aqueous magnesium nitrate, aqueous ammonium nitrate and aqueous ammoniacal ammonium nitrate;

(b) adding to the resulting blend from about 20 to about 35 parts by weight of a solution selected from the group consisting of aqueous magnesium nitrate, aqueous ammonium nitrate and aqueous ammoniacal ammonium nitrate;

(c) mixing the liquid and solid components to provide a substantially homogeneous composition;

(d) blending with said homogeneous composition an eiiective amount of a vinylidine chloride organic polymeric latex to increase the strength of said set explosive composition; and

(e) curing said composition to provide a dense, set,

water-resistant explosive composition.

10. The process as defined in claim 9 employing from about 50 to about 70 parts by weight particulate ammonium nitrate and from about 4 to about 8 parts by weight magnesium oxide to provide the initial blend of solids and having from about 22 to about 28 parts by weight of a substantially saturated solution selected from the group consisting of aqueous magnesium nitrate, aqueous ammonium nitrate and aqueous ammoniacal ammonium nitrate mixed therewith and from about 0.1 to about 10%, based on the weight of solids in said latex, of said latex.

11. The process as defined in claim 9 and including the step of incorporating up to about 50 parts by Weight of a particulated light metal into the initial blend of solids.

12. The method as defined in claim 9 wherein said latex References Cited is provided in an amount based on the solids present in said latex, ranging from about 0.1 to about 10% by weight UNITED STATES PATENTS of said composition Slykhouse 13. The method of claim 12 wherein said latex consists 5 essentially of fiom about to about by weight of STEPHEN LECHERT, Primary EXalIlinel vinylidene chloride and from about 65 to about 10% by weight of a dissimilar interpolymerizable comonomer, as US. Cl. X.R. based on a total interpolymeric latex solids content of 14943, 44, 60, 61 by weight. 10 

